The present invention relates to an improved support system to receive a patient or other individual confined to a wheelchair or other type seat for prolonged periods of time. Continued contact between the buttocks of an individual and the seat support therebeneath can create pressure on the buttocks leading to discomfort, decreased blood flow in the affected area and even the development of decubitus ulcers. The system of the present invention improves overall patient comfort, improves blood flow and reduces the incidence of development of ulcers.
Heretofore, a great deal of development effort has been expended toward improving wheelchairs and other types of seats which receive and hold non-ambulatory persons for extended periods of time. While great strides have been made for support systems for receipt of patients in a supine position so as to avoid the incidence of decubitus ulcers and the like, successes have not heretofore been achieved for patients in a sitting attitude. In fact, virtually no systems are known for use in wheelchairs and other similar type seats for improved prolonged sitting conditions with the exception of foam cushions of various densities and configurations, conventional air inflated cushions of various shapes and designs, gel filled cushions, water filled cushions and attenuating pressure pads or devices. In such prior art arrangements, the devices have generally been of singular construction, that is the entire surface of the support cushion is basically the same.
While support structures of the type described above do, in fact, add to the general comfort of the patient, constant pressures persist against the affected body portions of the patient such that ultimate discomfort results as well as a reduction of blood flow which could lead to the development of decubitus ulcers or pressure sores. In fact, since the whole upper body weight of a person is supported by the relatively small body area in the wheelchair seat, extremely high pressures may be experienced, up to about 200 mm Hg, on the ischial tuberosities. No system presently available as exemplified above is capable of achieving pressures low enough to prevent the development of pressure sores or ulcers in the most acute cases. No such system has thus been successfully employed in the wheelchair type environment as is contemplated by the present invention. Presently recommended techniques for wheelchair-ridden patients require the patient to periodically physically lift and hold himself off the cushion with his arms for as great a period of time as possible, thus removing pressure from the buttocks during the lift periods. While such techniques are certainly better than nothing, only limited success may be achieved thereby, while at the same time leading to extreme fatigue of the patient if the procedure is practiced over any extended period of time.
In general, body tissue without bony prominence thereunder will withstand higher pressures before tissue damage occurs. Conversely, body tissue having bony prominence therebeneath, such as the ischial tuberosities, is subject to the development of ulcers at lower surface pressures due to higher pressures generated at the tissue-bone interface. In order, therefore, to provide optimal support, it is necessary to provide a support system in which pressures generated on bony prominences, such as the ischial tuberosities is normally lower than the pressures on the surrounding areas of the buttocks.
The present invention achieves the aforementioned optimal situation, and provides a novel system for supporting a patient in a sitting position while at the same time improving patient comfort and reducing the incidence of the likelihood of development of decubitus ulcers. There is no known prior art that is believed to anticipate or suggest the present invention.